Prep: Preheat the oven to 350°F/180°c. Grease a 9 x 13 inch baking pan with non-stick cooking spray and set aside.
Prepare the zucchini by shredding it with a cheese grater and squeeze out some of the extra liquid with a paper towel.
Batter: Add the flour, sugar, cocoa powder, baking powder and salt to a large mixing bowl and whisk until well combined. Add the milk, oil and vanilla extract and whisk until well combined.
Mix in the eggs, add the boiling water (microwave to heat quickly) and the grated zucchini, mix carefully until well combined. Lastly, fold in the chocolate chips.
Bake: Pour the batter into the prepared baking tin, bake for 25 minutes, or until cooked through. Allow to cool completely in the tin.
Frosting: Chop the chocolate into small chunks and place them in a glass mixing bowl and set aside. This step is important as the chocolate will melt easier when in pieces.
Pour the heavy cream into a small saucepan, and bring to a simmer over a low heat.
Remove the cream from the heat and pour it over the chopped chocolate and let it sit for 2 minutes. Proceed to stir the chocolate until smooth and well combined. Allow the chocolate ganache to cool at room temperature for about 30 minutes.
Transfer the ganache to the bowl of a stand mixer, and beat with a wire whisk attachment for 4 minutes, or until pale in color and fluffy. The ganache can also be used without whipping. Simply spread over the cake once the ganache has cooled and thickened. After that, spread the topping over the cooled cake. Slice, serve and enjoy!